Sterile humidifier and method of operating same

ABSTRACT

A humidifier meters water into a chamber in which it is subjected to ultraviolet light for a predetermined period of time sufficient to destroy microorganisms whereupon the static quantity of water is transferred to a water dispersing unit which discharges the decontaminated water in a finely divided form into the environment.

FIELD OF THE INVENTION

[0001] The present invention relates to a humidifier utilizing ananticontamination field, for example ultraviolet radiation, and to amethod of operating such a humidifier.

BACKGROUND OF THE INVENTION

[0002] Commonly owned U.S. Pat. Nos. 5,859,952 and 5,677,982 disclosehumidifiers with anticontamination utilizing ultraviolet radiation orUV. The water is dispersed, after it has been subjected to antimicrobialinactivation by the ultraviolet radiation via an ultrasonic atomizer,heater or wettable surface or filter over which or through which air canbe passed. In that system the UV antimicrobial action takes place in achamber through which the water passes and which has at least one windowtransparent to the UV radiation so that the water in the chamber can beexposed to the UV.

[0003] While this system has proved to be effective in practice, it isfrequently desirable to afford greater assurance of the effectiveness ofthe antimicrobial field, namely, the ultraviolet radiation.

OBJECTS OF THE INVENTION

[0004] It is the principal object of the present invention to provide ahumidifier with an anticontamination field, especially UV, which canensure more effective UV decontamination than can be obtained withearlier systems.

[0005] Another object of the invention is to provide an improved methodof operating a humidifier which has an antimicrobial oranticontamination effect.

[0006] It is also an object to provide a method of operating ahumidifier and a humidifier operating operated by this method wherebythe antimicrobial efficiency is increased and sterile water is dispersedinto the environment without the need to heat the water to significanttemperatures.

SUMMARY OF THE INVENTION

[0007] These objects are achieved, in accordance with the inventionwhich is based upon the discovery that the disinfection oranticontamination effectiveness of a humidifier can be increaseddramatically by controlling the volume of the water subjected to thedecontamination field, i.e. the ultraviolet light, and the duration oftreatment of that quantity of water. By contrast with prior systems inwhich the water flow through the chamber was practically continuouswhile the humidifier was in operation, with the present invention ametered quantity of water is subjected to the ultraviolet radiationbefore it is passed to the water dispersal unit.

[0008] More particularly, the method of operating the humidifieraccording to the invention can comprise the steps of:

[0009] (a) intermittently feeding water to a sterilization chamber;

[0010] (b) exposing water in the chamber to a sterilization field for aduration and of a magnitude sufficient to inactivate microorganisms inthe water in the chamber; and

[0011] (c) thereafter dispersing the water from the chamber.

[0012] The humidifier itself can comprise:

[0013] a sterilization chamber;

[0014] a device for intermittently feeding water to the sterilizationchamber;

[0015] a source of a sterilizing field at the chamber for exposing waterin the chamber to the sterilization field for a duration and of amagnitude sufficient to inactivate microorganisms in the water in thechamber; and

[0016] a water disperser connected to the chamber for dispersing thewater from the chamber into the surroundings.

[0017] While in principle substantially any dispersion of the water intothe environment can be used, best results can be obtained when thedispersal is effected via an ultrasonic nebulizer, a rotary impeller orby filter, capillary or evaporation.

[0018] According to a feature of the invention, the amount of water iscontrolled by timing the inflow of the water to the chamber.

[0019] The inflow can be controlled by the timed operation of a solenoidor electromagnetic valve or by the controlled operation of a meteringpump on the upstream side of the chamber.

[0020] It has been found to be advantageous to have the chamberconfigured as an annulus and surround the UV lamp.

[0021] The timing can be effected by the control circuitry for thehumidifier.

[0022] All or part of the water path may be composed of or can containelements composed of a synthetic resin material containing a biocide.

BRIEF DESCRIPTION OF THE DRAWING

[0023] The above and other objects, features, and advantages will becomemore readily apparent from the following description, reference beingmade to the accompanying drawing in which:

[0024]FIG. 1 is a diagrammatic cross sectional view of a humidifierembodying the principles of the present invention;

[0025]FIG. 2 is a circuit diagram for that humidifier;

[0026]FIG. 3 is a diagram showing another means of water dispersal; and

[0027]FIG. 4 is a diagram of still another water dispersal unit whichcan be used with the humidifier of FIG. 1.

SPECIFIC DESCRIPTION

[0028] The humidifier 10 shown in FIG. 1 can comprise a base 11 formedwith a humidifier reservoir 1 which can be refilled from a tank mountedon the base and not shown. The water then flows through a tubing passage2 until it reaches a solenoid valve or pump 3 which, when energized,will open in the case of the solenoid valve and allow a metered amountof water to flow into an ultraviolet light water chamber 4. In the caseof a pump, a metered amount of water can be positively displaced via themeter 2 into the chamber 4. The decontamination chamber 4 is an annulushaving a tangential inlet 12 and a tangential outlet 13 and isinternally defined by a quartz wall 6 which may be a window transparentto UV light and through which the water in the chamber is exposed, orcan be the wall of an ultraviolet light source itself. In the presentcase, the source is a germicidal ultraviolet bulb 5 which illuminatesthe water in the chamber 4 through the walls 6. The wavelength of thelight from the germicidal UV bulb has been determined to kill thebacteria and other microorganisms.

[0029] The volume of water in the chamber 4 is selected for optimummicroorganism destruction and the duration in the water chamber 4 issubjected to the ultraviolet light is such that at least a largeproportion of the microorganisms which may be present in the water inthe chamber 4 is destroyed.

[0030] At the end of this time period, the solenoid valve or pump 3 isoperated so that the germicidally decontaminated water is delivered bytubing passage to an ultrasonic reservoir and provided with anultrasonic nebulizer transducer. The transducer oscillates at afrequency which produces a water mist released into the air through theopening 14 and discharged, if desired, directionally or nondirectionallyby a tube or duct surmounting the base 12. The water that enters theultrasonic reservoir 18 has spent enough time in the chamber 4 exposedto ultraviolet light to ensure that a significant proportion ofmicroorganisms are killed.

[0031] As can be seen from FIG. 3 instead of the ultrasonic nebulizer 10the tank 8 may be provided with a wick 55 by capillary action draws thesterile water up through the wick where a fan 16 blows the moisture intothe room.

[0032] In FIG. 4, the mist is produced by a rotary impeller 17 driven bythe motor 18.

[0033]FIG. 2 shows a circuit which can be used for the humidifier ofFIG. 1 and this circuit comprises a line 20 which can be connectable toa power source, such as an outlet, and has a fuse 21. The circuitincludes a step up transformer 22 which is utilized to operate anormally open solenoid valve 3 so as to close this solenoid valve forthe period in which the water in the disinfection chamber 4 is to besubjected to UV light from the lamp 5. The UV lamp 5 is energized by astandard UV light transformer 23 via a voltage control circuitconsisting of a zener diode 24 and a transistor 25. An LED 26 can signalfailure of the lamp 5. The circuit also includes a fan 27 as has beenmentioned previously to assist in distributing the moist air. Anebulizer transformer 28 is connected to the line 20 and operates thenebulizer 29 which can be cut off by a float switch 30 when there isinsufficient water in the nebulizer tank 8. A humidistat 31 may also beprovided to control the humidity level and an LED 32 can be provided tosignal the status of the apparatus. A rheostat 33 can control thenebulizer and switches can be provided as shown at 34 a, 34 b and 34 cfor on and off control or for control of the timing of the variousoperations.

[0034] In operation, of course, the valve 3 admits a quantity of waterto the chamber 4 and retains that quantity in the chamber for theduration of the exposure to the ultraviolet light and then opens topermit the decontaminated water to enter the chamber 8 from which it isdispersed. Because a static quantity of water is retained in the chamber4 for the full duration of the germicidal treatment, the extent of thegermicidal action can be guaranteed.

[0035] A plastic (synthetic resin) of the entire water path can containa biocide to prevent the growth of bacteria, fungi and othermicroorganisms and typical of these biocides are those which aremarketed under the names “BINYZINE” and “OMADINE”. The biocides can beincluded in any wick which may be employed. The water path may alsoinclude individual elements composed of plastic-containing biocides ormay have inserts which are impregnated with or include biocides in theircompositions.

[0036] I have found that the use of a biocide in conjunction with thegermicidal UV ensures excellent germ-free operation over the life of theapparatus.

[0037] Once the nebulizer tank is filled with the water sterilized bythe UV, the normally open solenoid valve 3 is switched off and becausethe valve remains open, the humidifier then acts like the humidifiersdescribed in the above-mentioned prior patents, i.e. can keep sendingsterilized water to the nebulizing chamber as long as the nebulizer isdimensioned so that the rate of evaporation corresponds to or is lessthan that that can be handled by the UV germicidal lamp and the geometryof the UV chamber.

[0038] In this way the valve remains deenergized and stays open untilthe power is turned off and then on again when the humidifier isrestarted. In this case, the valve can be energized only for 5 to 10minutes during a typical 24 hour operating period and has the advantageof preserving the solenoid coil of the valve whose overheating is amajor reason for appliance failures where solenoid valves are used.

I claim:
 1. A method of operating a humidifier comprising the steps of:(a) intermittently feeding water to a sterilization chamber; (b)exposing water in said chamber to a sterilization field for a durationand of a magnitude sufficient to inactivate microorganisms in the waterin said chamber; and (c) thereafter dispersing the water from saidchamber.
 2. The method designed in claim 1 wherein the water in saidchamber is subjected to ultraviolet light radiation to inactivate saidmicroorganisms.
 3. The method defined in claim 1 wherein said water fromsaid chamber is dispersed by ultrasonic nebulization.
 4. The methoddefined in claim 1 wherein said water is dispersed by contacting saidwater with a rotary impeller.
 5. The method defined in claim 1 whereinsaid water is dispersed by filter evaporation.
 6. The method defined inclaim 1, further comprising the step of controlling an amount of waterin said chamber by timing inflow of water to said chamber.
 7. Ahumidifier comprising: a sterilization chamber; a device forintermittently feeding water to said sterilization chamber; a source ofa sterilizing field at said chamber for exposing water in said chamberto said sterilization field for a duration and of a magnitude sufficientto inactivate microorganisms in the water in said chamber; and a waterdisperser connected to said chamber for dispersing the water from saidchamber into the surroundings.
 8. The humidifier defined in claim 7wherein the source of the sterilizing field is an ultraviolet lightsource.
 9. The humidifier defined in claim 7 wherein the device is anelectromagnetic valve communicating between a source of water and saidchamber.
 10. The humidifier defined in claim 7 wherein the device is apump connected between a source of water and said chamber.
 11. Thehumidifier defined in claim 7 wherein the water disperser is anultrasonic nebulizer.
 12. The humidifier defined in claim 7 wherein thewater disperser is a rotary impeller.
 13. The humidifier defined inclaim 7, further comprising timing circuitry connected to said devicefor controlling a duration of admission of water to said chamber. 14.The humidifier defined in claim 7, further comprising timing circuitryconnected to said source for controlling a duration of operation of saidsource.
 15. The humidifier defined in claim 7 wherein said source is anultraviolet lamp and said chamber surrounds said lamp, said devicecomprising a solenoid valve upstream of said chamber and between asource of water and said chamber, said humidifier comprising timingcircuitry for timing a duration of operation of said valve and aduration of operation of said lamp.
 16. The humidifier defined in claim15 wherein said water disperser is an ultrasonic transducer and saidcircuitry is connected to said ultrasonic transducer for energizing saidtransducer upon opening of said valve.
 17. The humidifier defined inclaim 16, further comprising a base provided with said chamber and onwhich said lamp, said transducer and said circuitry are mounted, saidbase being formed with a tank constituting said source of water.
 18. Thehumidifier defined in claim 7 wherein at least one element along thepath of said water between said device and a point at which water isdispersed into the surrounding is composed of a material containing abiocide.
 19. The humidifier defined in claim 18 wherein said waterdisperser is a wick and said wick contains said biocide.
 20. Thehumidifier defined in claim 9 wherein said electromagnetic valve is anormally open valve.